Published Monday, 19 January, 2009 at 02:47 PM
Minister for Primary Industries and Fisheries
The Honourable Tim Mulherin
Australia-first study proves roots prefer rest over rain
Researchers have proved that one of Queensland’s most important pasture grasses, Mitchell grass, responds better to a grazing spell than heavy rain during the wet season.
Primary Industries and Fisheries Minister Tim Mulherin said DPI&F west region researchers studied the effect of rain versus spelling on Mitchell grass and the results are clear.
“There is no doubt that Mitchell grass pastures respond better when they’re spelled instead of being over-grazed, because over-grazed pastures can’t make use of available moisture and nutrients to develop strong roots,” Mr Mulherin said.
“The research recommends if the Mitchell grass is growing from seed it needs to be spelled without grazing for one full wet season to establish strong, resilient roots.
“The good rains in the north-west provide the opportunity to quickly rebuild strong pastures. Spelling established pastures for five to six weeks now will allow Mitchell grass roots to re-establish. Spelling seedlings until the end of the wet season will allow robust root systems to grow. These strong pastures will provide years of future grazing,’ he said.
The research also showed that established Mitchell grass pastures need disturbances like grazing or fire to remain strong, otherwise they’ll go rank and die.
“Mitchell grass is a native plant that continues to provide feed through the winter months while other grasses lose their feed value,” the Minister said. “It is the backbone of the beef and wool industries in western Queensland.
“Without these native grasslands we’d lose about 60% of our cattle production in western Queensland. It also sustains 40% of the state’s merino flock.
“However, in recent years Mitchell grass pastures have become badly depleted through drought and overgrazing, with an estimated 53% of pastures in poor condition.
“The poor condition of these pastures is costing Queensland $93 million a year in reduced livestock carrying capacity,” the Minister said.
“Individual Mitchell grass plants can live for 20 to 30 years, and mature plants are well adapted to Queensland’s harsh environment, coping with droughts through a deep root system and reserves of starch.
“These reserves are used to promote new growth when sufficient rainfall occurs.
“Because of the erratic nature of rainfall and droughts in outback Queensland, mature plants produce new seedlings just once or twice over this period,” Mr Mulherin said.
Recently the DPI&F, led by principal scientist Dr David Phelps, conducted world first research at the department’s Rosebank research station near Longreach, studying the effects of rain versus spelling.
“At workshops we have held throughout the state, graziers repeatedly asked for advice on how to replenish their Mitchell grass with most graziers believing that the next “big wet” will fix all their problems,” Dr Phelps said.
“There is no disputing the importance of rain for pasture growth, but months of research has found resting the seedlings and spelling established grasslands is the most important factor for sustainable pastures,” he said.
“There is no doubt giving the seedlings a chance to rest allows them to grow a longer, more robust root system,” he said.
“No-one in Australia had done any research on this scale and when we spoke with graziers at public forums and Grazing Land Management (GLM) workshops it was raised over and over again,” Dr Phelps said.
“We found the most effective way to promote a natural root system was to grow the Mitchell grass seedlings in huge, reinforced cardboard boxes that held a tonne and a half of soil,” Dr Phelps said.
“The team spent a few very muddy days carefully washing all that soil off the roots so we could study and compare their growth.”
All this hard work has been recognised within the DPI&F with the Mitchell grass recovery research team named finalists in the 2008 staff awards.
Dr Phelps said the awards acknowledge the quality and breadth of work being undertaken across the department.
“This is relevant, practical science and our findings will help graziers and other land managers across the country,” he said.
The Mitchell grass research was funded by Desert Channels Queensland (DCQ).
Media: Matt Watson 3239 3120
Primary Industries and Fisheries Minister Tim Mulherin said DPI&F west region researchers studied the effect of rain versus spelling on Mitchell grass and the results are clear.
“There is no doubt that Mitchell grass pastures respond better when they’re spelled instead of being over-grazed, because over-grazed pastures can’t make use of available moisture and nutrients to develop strong roots,” Mr Mulherin said.
“The research recommends if the Mitchell grass is growing from seed it needs to be spelled without grazing for one full wet season to establish strong, resilient roots.
“The good rains in the north-west provide the opportunity to quickly rebuild strong pastures. Spelling established pastures for five to six weeks now will allow Mitchell grass roots to re-establish. Spelling seedlings until the end of the wet season will allow robust root systems to grow. These strong pastures will provide years of future grazing,’ he said.
The research also showed that established Mitchell grass pastures need disturbances like grazing or fire to remain strong, otherwise they’ll go rank and die.
“Mitchell grass is a native plant that continues to provide feed through the winter months while other grasses lose their feed value,” the Minister said. “It is the backbone of the beef and wool industries in western Queensland.
“Without these native grasslands we’d lose about 60% of our cattle production in western Queensland. It also sustains 40% of the state’s merino flock.
“However, in recent years Mitchell grass pastures have become badly depleted through drought and overgrazing, with an estimated 53% of pastures in poor condition.
“The poor condition of these pastures is costing Queensland $93 million a year in reduced livestock carrying capacity,” the Minister said.
“Individual Mitchell grass plants can live for 20 to 30 years, and mature plants are well adapted to Queensland’s harsh environment, coping with droughts through a deep root system and reserves of starch.
“These reserves are used to promote new growth when sufficient rainfall occurs.
“Because of the erratic nature of rainfall and droughts in outback Queensland, mature plants produce new seedlings just once or twice over this period,” Mr Mulherin said.
Recently the DPI&F, led by principal scientist Dr David Phelps, conducted world first research at the department’s Rosebank research station near Longreach, studying the effects of rain versus spelling.
“At workshops we have held throughout the state, graziers repeatedly asked for advice on how to replenish their Mitchell grass with most graziers believing that the next “big wet” will fix all their problems,” Dr Phelps said.
“There is no disputing the importance of rain for pasture growth, but months of research has found resting the seedlings and spelling established grasslands is the most important factor for sustainable pastures,” he said.
“There is no doubt giving the seedlings a chance to rest allows them to grow a longer, more robust root system,” he said.
“No-one in Australia had done any research on this scale and when we spoke with graziers at public forums and Grazing Land Management (GLM) workshops it was raised over and over again,” Dr Phelps said.
“We found the most effective way to promote a natural root system was to grow the Mitchell grass seedlings in huge, reinforced cardboard boxes that held a tonne and a half of soil,” Dr Phelps said.
“The team spent a few very muddy days carefully washing all that soil off the roots so we could study and compare their growth.”
All this hard work has been recognised within the DPI&F with the Mitchell grass recovery research team named finalists in the 2008 staff awards.
Dr Phelps said the awards acknowledge the quality and breadth of work being undertaken across the department.
“This is relevant, practical science and our findings will help graziers and other land managers across the country,” he said.
The Mitchell grass research was funded by Desert Channels Queensland (DCQ).
Media: Matt Watson 3239 3120